"Unless otherwise required by law or to the extent we reasonably deem necessary to protect our rights, property, or safety, and the rights, property, and safety of our users, we will delete Personal Information when: (1) it is no longer necessary in relation to the purposes for which it was collected... if this is not possible (for example, because the information has been stored in backup archives), then we will securely store your information and isolate it from any further use until deletion is possible."
FlightAware provides no specific retention timelines and carves out broad exceptions allowing indefinite retention for legal, safety, or business reasons, including keeping data in backup archives indefinitely.